Method and kit for examining complement system

Abstract

A method for examining a complement system of a subject, including: a reaction step of letting a scavenger receptor or a functional equivalent thereof, a pentraxin family protein or a functional equivalent thereof and a blood sample collected from the subject coexist in vitro; and a detection step of detecting complement activation amplifying reaction and/or complement activation late-phase reaction induced by interaction between the scavenger receptor or the functional equivalent thereof and the pentraxin family protein or the functional equivalent thereof from a reactant after the reaction step. Also provided are a kit for examining a complement system, and a method for testing a test substance for the ability to activate or suppress a complement system.

What is claimed is: 
     
         1 . A method for examining a complement system of a subject, comprising:
 a reaction step of letting a scavenger receptor or a functional equivalent thereof, a pentraxin family protein or a functional equivalent thereof and a blood sample collected from the subject coexist in vitro; and   a detection step of detecting complement activation amplifying reaction and/or complement activation late-phase reaction induced by interaction between the scavenger receptor or the functional equivalent thereof and the pentraxin family protein or the functional equivalent thereof from a reactant after the reaction step.   
     
     
         2 . The method according to  claim 1 , wherein in the detection step, complement activation early-phase reaction is further detected. 
     
     
         3 . The method according to  claim 1 , wherein the reaction step is a step of letting the scavenger receptor or the functional equivalent thereof existing on mammalian cells, the pentraxin family protein or the functional equivalent thereof and the blood sample collected from the subject coexist. 
     
     
         4 . The method according to  claim 3 , wherein the mammalian cells are human cells. 
     
     
         5 . The method according to  claim 3 , wherein the mammalian cells are human embryonic kidney-derived cells. 
     
     
         6 . The method according to  claim 1 , wherein the reaction step is a step of letting the scavenger receptor or the functional equivalent thereof immobilized on a support, the pentraxin family protein or the functional equivalent thereof and the blood sample collected from the subject coexist. 
     
     
         7 . The method according to  claim 6 , wherein the functional equivalent of the scavenger receptor is a peptide fragment containing an extracellular domain of the scavenger receptor. 
     
     
         8 . The method according to  claim 1 , wherein the scavenger receptor is CL-P1, SR-AI or LOX-1. 
     
     
         9 . The method according to  claim 1 , wherein the pentraxin family protein is C-reactive protein, serum amyloid P component or pentraxin 3. 
     
     
         10 . The method according to  claim 1 , wherein the detection of the complement activation amplifying reaction is conducted by detection of properdin and/or factor B or a degradation product thereof. 
     
     
         11 . The method according to  claim 1 , wherein the detection of the complement activation late-phase reaction is conducted by detection of C5b-9. 
     
     
         12 . The method according to  claim 2 , wherein the detection of the complement activation early-phase reaction is conducted by detection of a C3 degradation product. 
     
     
         13 . A kit for examining a complement system, comprising:
 human cells expressing a scavenger receptor or a functional equivalent thereof; and   a pentraxin family protein or a functional equivalent thereof.   
     
     
         14 . A method for testing a test substance for the ability to activate or the ability to suppress a complement system, comprising:
 a test substance reaction step of letting a scavenger receptor or a functional equivalent thereof, a pentraxin family protein or a functional equivalent thereof, a blood sample and a test substance coexist in vitro;   a control reaction step of letting a scavenger receptor or a functional equivalent thereof, a pentraxin family protein or a functional equivalent thereof and a blood sample coexist in vitro;   a detection step of detecting complement activation amplifying reaction and/or complement activation late-phase reaction induced by interaction between the scavenger receptor or the functional equivalent thereof and the pentraxin family protein or the functional equivalent thereof from a reactant after each reaction step; and   a determination step of determining that the test substance has the ability to activate the complement system when the complement activation amplifying reaction and/or the complement activation late-phase reaction detected from the reactant after the test substance reaction step is larger than the complement activation amplifying reaction and/or the complement activation late-phase reaction detected from the reactant after the control reaction step, and determining that the test substance has the ability to suppress the complement system when the complement activation amplifying reaction and/or the complement activation late-phase reaction detected from the reactant after the test substance reaction step is smaller than the complement activation amplifying reaction and/or the complement activation late-phase reaction detected from the reactant after the control reaction step.